MOSCOW, December 4 /TASS/. Russian warplanes have destroyed 12 fuel pump stations, 8 oil fields and oil and gas facilities; as well as more than 170 extremist-owned tanker trucks in a week, Russian Defense Ministry Spokesperson Igor Konashenkov said on Friday.

"Twelve fuel pump stations, 8 oil fields and oil and gas facilities as well as more than 170 tanker trucks have been destroyed (in Syria) over the past week," Konashenkov said.

Russia’s Sukhoi-34 bombers over the past day have destroyed several dozen tanker trucks and other vehicles for transporting oil products, Igor Konashenkov told a news briefing.

"Over the past day alone Sukhoi-34 bombers attacked two truck convoys on the roads in the areas of Aleppo and Raqqah to destroy up to 40 tanker trucks and other vehicles equipped for transporting fuel supplies," Konashenkov said.

Earlier, the Defense Ministry said that Russian air strikes had caused the militants’ incomes from illegal oil trade to fall by half from $3 million to $1.5 million. The terrorists have at their disposal about 8,500 tanker trucks carrying more than 200,000 barrels of crude a day.

Terrorists in Syria are suffering serious losses, are demoralized and seeking to desert their positions, Igor Konashenkov said.

"We’re registering these facts more and more frequently and this information is confirmed by various channels," he said. "The militants are suffering serious losses are demoralized and seeking to clear out of their positions. For instance, they abandoned positions in the vicinity of Jebel Rumeli, Hazem al-Abyat and Wadi al-Sayyah."

Russian military also tracked down a disguised command center of the terrorists where from they had been coordinating artillery fire at population centers.

"Aircraft strikes fully destroyed the center and fully disoriented the steering of artillery strikes in the area," Gen Konashenkov said.

Russian warplanes have been delivering air strikes at terrorist targets in Syria since September 30 this year at the request of Syrian President Bashar al-Assad. The military said in mid-November that they would focus the air strikes on facilities for the production, storage, transportation and processing of fuel controlled by the Islamic State militants.

The Islamic State terrorist group is banned in Russia as a terrorist organization.